Dredge.



I G. MCKAY.

D R E D G E.

(Application filed May 2, 1901,)

(No Medel.)

Patented Aug. 5, |902.

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2vSheets-Sheet 2.

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UNTTED STATES PATENT OFFICE.

GORDON IWIOKAY, OF NEVPORT, RHODE ISLND.v

DREDGE.

SPECIFICATION forming part of Letters Patent No. 706,195, dated August5, 1902.

ipplication filed May 2.1901. Serial. No. 58,506. (No model.)

To all whom, it may concern:

Be it known that I, GORDON MCKAY, a citizen of the United States,residing at Newport, county of Newport, State of Rhode. Island, haveinvented an Improvement in Dredges, of which the following description,in connection with the accompanying drawings, is a specification, likecharacters on the drawings representing like parts.

This invention relates to an apparatus which is adapted for use inplacer-mining.

As is well known, alluvial deposits are oftentimes rich in gold or otherprecious metals, and in extracting thegold from such auriferous materialsome suitable form of dredging or excavating mechanism is employed whichdigs up the material and deposits it in a suitable sluiee, where it iswashed and the gold extracted in a well-known way. In order toconveniently carry on the dredging or excavating operation, anartificial pond is generally made over the place where the gold-bearingalluvial deposits are, and the excavating or dredging device is mountedupon a suitable scow, which is moored or floated on such pond. In theprocess of extracting the precious metals, such as gold, from theauriferous material such material is dug up and deposited in a suitablescreening device, Which allows the ner material to pass through, butdelivers the coarse tailings over the side of the scow, the iinermaterial dropping into a suitable sluice, where it is washed and thegold extracted in the usual way. When the dredging operations arecarried on under an artificial pond, as above described, it becomesimportant that the least depth of water in the articial pond should beemployed consistent with the free and proper swinging movement of thescow, for the deeper the water the more expense the dredging operationsentail. It becomes necessary, therefore, to provide some systematic wayof distributing or deliveringthe tailings from the dredge, so as toprevent the same from accumulating under the scow or in any part of theartiiicial pond in such a wayas to prevent or obstruct the free movementof the scow7 for it will be obvious that if the tailings were dischargedin an indiscriminate way, so as to be deposited in heaps, the depth ofthe water in the artificial pond would have to be so great that themovement of the scow over the pond would not be interfered with by thedeposits.

It is the object of my invention to construct an apparatus adapted forplacer-mim ing which includes means for systematically distributing thetailings from the screens and sluices, which are mounted on the scow,said distribution of the tailings taking place in such a way that aminimum depth of water in the artificial pond is sufficient.

In accordance with my in vention the material which is lifted by thedredge is divided into two portions, the coarse material beingpreferably separated from the finer material, and the coarse material isdischarged over the sides of the scow, near the front portion thereof,while the finer tailings are discharged from the back end of the scow.The result is that when the scow is in operation a comparatively deepexcavation will exist under the front of the scow while the dredge is atwork lifting the material, While the back portion of the scow will besituated over the deposit ot' the coarser tailings, which will partiallyfill up the deep excavation, but which will still allow sufficient depthot' water for the scow to freely swing about its pivot. The finetailings are delivered back of the scow, where the dredging operationshave been performed, and even though the said finer tailings fill up thesurface of the'pond to such an extent that the scow would not lioat overWhere the tailings have been deposited, yet because the scow is situatedover the partially-filled excavation it has sufficient depth ot' waterin which to move.

With this object in View my invention comprises a scow or lioat which ismounted for swinging movement upon a body of water about a center at oneend thereof, and at the other end'the said scow has a suitableexcavating device, which is adapted to dig up the aurit'erous materialand deposit the same into two oppositely-arranged rotating screens orgrizzlies, the said grizzlies being situated some distance in front ofthe pivotal center of the scow and having their discharge endsprojecting over the opposite sides of the scow. A sluice having rillesis carried by the scow and has at one end a receiving portion situatedunderneath the grizzlies, the opposite end of the sluice extending somedistance ICO beyond the pivoted end of the scow and being supported upona suitable float, the said sluice being either rigidly fixed to the scowor madewith a joint near Where the sluice passes the back end of thescow, so that the projecting end ofthe sluice may swing about suchjoint, and thus be deflected to either side. By virtue of thisconstruction as the dredging operation is carried on and the scow isgradually swung about its center the rotating screens or grizzlies lwilloperate to screen the dredged material, and the coarser material, whichdoes not pass through the screens, will be deposited either side of andbeneath `the scow and on an arc parallel to the arc on which theexcavator works, while the finer tailings will be deposited from the endof the `sluice which projects some distance beyond the stern of thescow, and will thus be deposited upon top of the coarser tailings. Itwill be seen, therefore, that the scow is always situated parrially overthe excavated place and partially over the deposit of the coarsertailings, and since such coarse tailings are not sufficient tocompletely fill the excavated placethe water will be deeper immediatelyunder the scow than in those places where the excavation has not beencarried on or where the finer tailings from the sluice have beendeposited on top of the coarser tailings from the screens. With myinvention, therefore, the material after having the gold extractedtherefrom is deposited in much the same position that it was beforeworking it that is, the larger stones and coarser gravel are at thebottom and the finer material on top.

Figure 1 is a top plan View of my apparatus. Fig. 2 is a section takenthrough the dredge just back of the grizzlies. Fig. 3 is a sideelevation showing in dotted line the manner in which'the tailings aredeposited. Fig. 4 is a' detail of the deflector hereinafter referred to.Fig. 5 is a sectional detail of the grizzlies, showing the means forvarying the size of the openings therein; and Fig. 6 is a longitudinalsection through the joint of the Screen.

S denotes a scow or float upon which the machinery used in the dredgingand mining apparatus is mounted, and, as customary in dredgingoperationsthe scow is mounted for swinging movement by constructing thescow at one end with the post 50, from the upper end of which areextended guy-ropes 52 53 54* 55, which are fastened to any suitablewindlasses or dead-men u pon the shores. The front end of the scow hasattached thereto in any suitable way the ropes or cables 57 5S, which inturn lead to windlasses or dead-men on the opposite shores ofk thestream and by means of which the scow may be swung about its pivotalpoint, as will be obvious. The scow is made at its front end with theusual well W, .in which operates the ladder 15, on which is supportedthe usual chain-andbucket excavator 21, the said ladder being pivoted atits upper end upon a shaft 14, supported in suitable uprights 12 and 13upon the scow. This form of chain-and-bucket excavator being familiarand well known in the art further description is not necessary. Thefront end of the ladder 15 has connected thereto the yoke 26, to whichis connected the rope 22, said rope passing over a pulley 23 in the endof the bent arm 24, rigidly mounted at the front end of the scow, thesaid rope being secured at its free end to any suitable attaching meansand serving as a means for maintaining the excavator at any desiredelevation. The excavating device operates to dig the material from thealluvial deposit and carry it to two oppositely-disposed grizzlies orrotating screens, (designated, respectively, by G and G,)the saidgrizzlies being supported for rotation in any suitable way and atsuitable places upon the scow. The discharge or delivery ends of thegrizzlies extend beyond the gunwales of the scow, and they are adaptedto discharge the coarser material, such as large stones and coarsegravel which are received from the dredger, into the excavation or holemade by the dredge and on each side of the scow, as shown in Figs. 1 and3. The grizzlies are inclined somewhat, as seen in Fig. 2, in order tofacilitate the gravitation of the gravel or coarse material through thesame, or the gravel maybe carried along by spirallyarrangedfeather-blades inside the grizzlies, the feed of the material of coursebeing aided bythe rotation of the grizzlies. The inner or receiving endsof the grzzlies are pro- Vided with the teeth 41, which mesh with gears42 upon the shaft 14, by means of which construction the rotation ofsaid shaft 14 operates to rotate the grizzlies,it beingunderstood thatthe shaft 14 is connected to and operated by `any suitable engine ormotor upon the scow.

Fig. 5 illustrates in detail the construction of the screen or grizzly,the cylindrical body 3 thereof having a series of screw-threadedapertures therein, into which are screwed bushings or hollow plugs 4,byreason of which construction plugs with larger or smaller aper-y turestherein may be used to regulate the degree of iineness in the screeningand the depth of the water under the scow, as hereinafter explained.

S/ designates a sluice which will have suitable riffles or othergold-catching means therein, said sluice having at its forward end thehopper or receiving portion 30, which extends underneath both grizzliesand serves to catch the finer material which passes through ltheapertures therein, the said receiving portion 30 being supported in somesuitable way upon the scow. The sluice is usually rigid with loi IIO

the scow and extends beyond the pivoted end thereof for a distanceapproximately equal -to the length of the scow, and when the wholesluice is rigid its discharging end swings upon an arc as the scow movesabout its center, the free end of the sluice being supportedy upon asuitable float 33. As it is often desirable to turn the scow around onits pivoted point to proceed in a different direction, it is convenientto turn the sluice at an angle with the center line of the scow. I maytherefore make my sluice with a swinging joint near the back end of thescow, as seen in Fig. 6, and guy-ropes 5, attached to the end of thesluice, may be used to swing the said sluice in either direction and tohold the same rigid when it has been brought into the desired position,the said guy-ropes being operated by any well-known Winding mechanism onthe scow. The joint in the sluice is shown in Fig. 6, and, asillustrated, the portion 32 of the sluice is rigid with the scow and isprovided with the overhanging circular end 7, having the dependingcircular fiange 8. The projecting portion 9 of the sluice has theupturned circular flange 10, which registers with the flange 8, and thetwo portions 32 and 9 of the sluice are secured together for relativeturning movement by the pivot-pin 11. In order to stiffen the circularflanges 8 and 10, their meeting edges are provided with angleirons 12,and to make the joint tight I secure to the inside of the fiange 8 anannular leather packing 13, which overlaps the joint, as seen in Fig. 6.As illustrated in the drawings, the post 50, to which the guy-ropes 5253 54 55 are attached, is made forked at its lower end to provide anopening through which the sluice may pass, as plainly seen in Fig. l.

In order that the amount of material received by each grizzly, andconsequently the amount discharged therefrom, shall be approximately thesame, I have provided a movable deiiector, (shown enlarged in Fig. 4,)designated by D, which maybe adjusted to carry more or less gravel intoeither grizzly, this being convenient, because when the scow is swingingto one side the buckets will come up more heavily loaded on that sidetoward which the scow is being fed, and by means of the deiiector I caninsure the proper distribution of the material to each grizzly. Thedeflector, as shown, is of substantially inverted-V shape, and betweenthe two oppositely-inclined portions 61 thereof, which cooperate,respectively, with the grizzlies G G', the lever 62 is secured, saidlever being pivoted, as at 63, to the bearingor bracket 64 upon the oorof the scow. Preferably the deiiector will be provided with flanges orWalls 65, which direct or discharge the material into the grizzlies. Thelower end of the lever 62 is provided-With a nut 73, which engages thescrew-thread 7 2 on a shaft 70, which construction enables the peak ofthe dei'iector to be moved either side of the central position, so as tobring the same in proper position to divide the material as it isdischarged from the buckets into approximately equal portions, eachequal portion moving down or being directed by one of the inclines 60 61into the adjacent grizzly.

In Fig. 1 the dotted line a; illustrates the line on which the dredgingor excavating device operates, and the dotted line y indicates the lineon which the coarser tailings from .vated place, as shown in the dottedline at d in Fig. 3, while the dotted linee indicates the i line uponwhich the finer tailings are deposited directly back of the scow, thesefiner tailings further filling up the excavated place, as shown at l) inFig. 3. The scow, therefore, is situated partially over the excavatedplace and partially over the deposit ct from the grizzlies, as seen inFig. 3, and obviously the water is deeper in this place than where thetailings from the sluice are deposited, as at l). It will be obvious,therefore, that even though the depth of the water in the unexcavatedplaces in the artificial pond or in the path or portion which hasalready been excavated and which has been filled again by both the fineand the coarse tailings is insufficient to properly iioat the scow, yetsince the scow is supported in the deeper Water over thepartially-filled excavation, as shown in Fig. 8, the movement of thescow is perfectly free and is not in any way obstructed. It becomespossible, therefore, to employ in the artificial pond a minimum depth ofwater, which is a decidedadvantage in apparatus of this class. By makingprovision for varying the size of the apertures through the grizzlies Ican regulate at will the amount of tailings discharged therefrom andheight of the deposit a, and consequently the depth of the Water whenthe scow is moored, and by depositing the coarse tailings inapproximately even quantities on both sides of the scow there is nodanger of the same piling up and interfering with the free movement ofthe scow. Moreover, it is desirable that as large a proportion of thetailings as possible be deposited from the grizzlies Without groundingthe scow, for the amount of water required in the sluice is therebyreduced. By my construction I can regulate the amount discharged fromthe grizzlies so as to secure this result, and I consider this animportant feature of my invention.

It will be obvious, of course, that various changes may be made in theconstruction of the parts without departing from the spirit of myinvention. For instance, the various guy-ropes may be operated bymechanism on the scow, or a single grizzly may be placed IOD IIO

2.. In an apparatus of the class described, a scow, a dredging'device atone end thereof, two oppositely-disposed grizzlies located to receivethe material from the dredging de-r vice and deliver the coarsortailings at either side of the scow, combined vwith a sluice located to`receive the fine material from the grizzlies and deliver the tinetailings to the rear of the scow.

3. In an apparatus of the class described, a scow, a dredging device atone end thereof, mechanism for separating the coarse gravel from thefine and valuable material, said separating mechanism having sidedischarges whereby the coarse gravel is deposited either side of thescow, a sluice adapted to receive the fine material from the separatingmechanisms, said sluice extending back from the scow and having itsprojecting end pivotally mounted, and means to maintain the pivoted endof the sluice in any adjusted position.

4. In an apparatus of the class described, a scow pivoted for swingingmovement about one end, an excavating device on the 'front end of saidscow, two oppositely-disposed rotating grizzlies or screens in front ofthepivotal point of the scow, and projecting at their discharge endsover the sides of the scow, said grizzlies receiving material from theexcavator and operating to discharge the coarse tailings on both sidesof the scow, a sluice adapted to receive ne material from the grizzlies,said sluice being attached to the scow and extending back thereof a.distance approximately equal to the length of the scow,

f and a fioat to support the end of the sluice,

5. In an apparatus of the class described, i

a scow pivoted for swinging movement about one end, an excavating deviceon the front end of said scow, two oppositely-disposed rotatinggrizzlies or screens in front of the pivotal point of the scow, saidgrizzlies receiving material from the excavating device and operating todischarge the coarsetailings on either side of the scow, a sluiceadapted to receive the fine material from the grizzlies, said sluicebeing attached to the scow and extending back thereof a distanceapproximately equal to the length of the scow.

6. In an apparatus ofr the class described, a scow or float, a dredgecarried thereby, means to separate the coarse gravel from the fine andvaluable material, a sluice to receive the fine material, said sluiceextending back from the scow, and comprising two sections` one of saidsections rigid with the scow and havingat its end a joint articulatingwith the end of the other section, and means for varying the relativepositions of the two seotions and for holding them in any adjustedrelative position, whereby one section may have a lateral swingingmovement relative to the'other, or may be made rigid therewith.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing Witnesses.

GORDON MCKAY. Witnesses:

LoUIs C. SMITH, GEO. W. GREGORY.

